Look at the speed tiers:
http://www.smogon.com/forums/threads/battle-maison-discussion-records.3492706/page-53#post-5265230
For base 100s, these are the Pokemon between Jolly and Adamant (inclusive):
167 - Flygon (1,2,3), Miltank (1,2,4), Ninetales (2,3,4), Salamence (3,4), Slaking (1,2,4), Staraptor (1,4), Starmie 2, Tentacruel (1,2), Typhlosion 2, Volcarona 2, Zapdos (1,3,4)
165 - Durant 1, Hydreigon (3,4), Serperior 4
163 - Haxorus (1,3,4)
162 - Archeops 2, Espeon 3, Froslass 2, Latias 4, Latios 4, Raichu 1, Tauros 1
161 - Arcanine (3,4), Darmanitan 1, Drapion (2,3), Durant 2, Electivire 4, Gliscor 4, Houndoom (2,3,4), Jynx 4, Leafeon 2
160 - Electrode 1
159 - Unfezant (2,3)
158 - Pyroar (3,4), Krookodile 4
157 - Manectric (1,2), Rapidash 1
156 - Delphox (2,4), Kangaskhan (2,3,4), Lilligant 1, Lucario (2,3), Moltres (3,4), Porygon-Z 4, Roserade 3
152 - Charizard (2,4), Entei 1, Flygon 4, Ninetales 1, Staraptor 3, Typhlosion (1,4), Volcarona 1
Most of these don't appear after battle 40. Excluding those that don't (as well as ones who are only used by one trainer after battle 40) leaves us with:
167 - Miltank 4, Ninetales 4, Salamence (3,4), Slaking 4, Staraptor 4, Typhlosion 2, Zapdos (1,3,4)
165 - Hydreigon 4, Serperior 4
163 - Haxorus 4
162 - Espeon 3, Latias 4, Latios 4
161 - Arcanine 4, Electivire 4, Gliscor 4, Houndoom 4, Jynx 4, Leafeon 2
159 - Unfezant 3
158 - Pyroar 4, Krookodile 4
156 - Delphox (2,4), Kangaskhan 4, Moltres (3,4), Porygon-Z 4
152 - Charizard (2,4), Entei 1, Flygon 4, Staraptor 3, Typhlosion (1,4), Volcarona 1
Most people don't want to weaken their attackers for the sake of a speed tie, so the 167 group is out already. Many of the remaining Pokemon aren't particularly good match-ups for Charizard anyway (Dragon Pulse won't OHKO the Lati twins and isn't a guaranteed OHKO on Flygon, Fire-types resist your strongest STAB and may have Flash Fire for immunity), or simply aren't considered threatening enough to warrant a Jolly nature (Krookodile 4 really isn't very strong; Mega Zard Y handily beats Kangaskhan 4 anyway). Jynx is probably the most annoying opponent of the bunch who you'd really like to KO (due to the threat of Lovely Kiss), but it's generally easier to have a teammate take care of her than to weaken MegaZard Y against almost every other opponent.
Mega Kangaskhan handles most of these opponents with Sucker Punch anyway, and often can't be OHKO'd by them even with a crit, meaning the extra speed is irrelevant more often than not.